Surfacing finishing machine



April 14, 1942. B. F. FOWLER SURFACE FINISHING MACHINE Filed Aug. 23, 1939 4 Sheets-Sheet l INVENTOR. BE/ET P FOWZ 52a 24/ ATTORNEYS April 14, 1942. FOWLER 2,279,783

SURFACE FINISHING MACHINE Filed Aug. 25, 1939 4 Sheets-Sheet 2 III/I1.

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r 3a) x INVENTOR. Q .BFIETFFOWZE'IE BY 9' m."

'. ATTORNEYS April 14, 1942. B; F. FOWLER SURFACE FINISHING MACHINE Filed Aug. 25, 1959 4 Sheets-Sheet s INVENTOR. 35787 F POM/[L E ATTORNEYS p i 1942. B. F. FOWLER 2,279,783

I I SURFACE FINISHING MACHINE Filed Au 23, 1959 v 4 Sheets-Sheet 4 ffgafzz I INVENTOR- 34-787 7-? 70 W1 5;?

' ATTORNEYS Patented Apr. 14, N42 1 UNITED w p I 2,279,783-

susmomormrsnmo MACHINE Bert F. Fowler, South Bend, Ind. Application August 23, 1939, Serial No. 291,536

7Claims. (01. 51-170 This invention relates to the art of surface finishing and more particularly to apparatus for producing a smooth, fine surface on. either bare metal or paint.

My improved machine belongs to the general class of devices known as sanding machines and although it is particularly adapted for the wet sanding of painted surfaces, such as the priming coat on an automobile body, it may also be used as a dry sanding machine, on metal surfaces or for other sanding or polishing operations. a

In the production of automobile bodies, metal furniture, railroad cars, etc.,iunder present day practice the properly smoothed and prepared metal surfaces are given a coat of priming paint which dries with a relatively rough and uneven surface even though the metal surfaceto which it is applied may be quite smooth. Prior to my invention it has been the common procedure to hand rub this priming coat with wet sandpaper to give it the necessary smoothness to take the final coats of lacquer, enamel or paint. This hand sanding is necessarily an'e'xpensive and laborious job and even the mostgskilled workmen cannot obtain a perfectly smooth and uniform surface due to the-fact thatthe human hand does not exert a uniformipressure at all points when used to backup apiece of abrasive paper. v

It is among the objects of my present invention to provide a surface finishing machine which can be employed for wet sanding operations with perfect safety to the operator and which will give an extremely uniform and fine finish.

Other objects of my invention include: the provision of a sanding machine which, although particularly adapted for wet sanding in paint finishing operations, may also be used *in-dry surfacing operations on bare metal; the provision of a surface finishing machine which can be operated by relatively unskilled workmen, and

energy required to give the desired surface finish on the priming coats of automobile bodies or the like; the provision of a sanding machine of the driven belt type in which uniformly resilient means are provided for backing up the belt whereby an extremely smooth, fine surface results; the provision of a sanding machine of the type described which is entirelyv free fromelectrical connections and may thus be used with complete safety for wetfinishing operations; and the provision of a surface finishing machine which is adapted for use, either on vconcave: or

I which greatly reduces the amount of human convex surfaces and which, may readily be'con-i verted from one type of machine ;to another.

The above and, other objects of my invention will appear from the followingdescription; of two embodiments thereof, reference being had to the accompanying drawings, in which- Figure 1" is aside elevation of one of my improvedmachines which isparticularly adapted forwetfinishing. Q

Figure 2 is a; cross-gsectional view taken substantially on line 2520f; Figure 1.

Figure '3 is what might be termed a bottom view of the apparatus shown-in Figures 1 and 2, portions being broken away-for purposes of clearer illustration. 2 v

Figure 4 is'a fragmentary detached View taken on line 4-4 of Figurel illustrating the driving connections from the air motor to the main drive pulley. j j y I i.

Figure 5 is a detached fragmentary crosssectional view taken on line 5-5 of Figure 1.

' Figure 6 isa detached fragmentary view of the resilient backing belt used on the apparatus shownin Figures 1 to 5, v 1

Figure f? is a side elevational viewof a modified form of my invention which is particularly adapted for the sanding of convex surfaces having a relatively largeradius.

Figure 8 is afragmentary, view illustrating the left hand endof Figure 7=-with theroll adjusting mechanism shown in'cross-section.

Figurefi is a view similar to FigureB but illustrating the right hand end-of the apparatus of Figure '7, the roll moving cylinder being shown in cross-section; Y a i Figure 10 is a vertical" cross-sectional view taken on line|0--I 0-,of;Figure 7. j

Figurell is a view generallysimilar to Figure '7 but showing the machineof Figure 7. with an auxiliary "belt backing i-roll;

Figure .12 is .a horizontal cross-sectional.view taken on line l2| 2' of Figure 11.

Referring particularlyto Figures 1 to 6 inclusive, a'main frame structure I. carries the ,air motor 2, which maybe .ofany suitable type; Air is supplied-to the motorZ. through a flexible hose-3 which is connected to a source. of supply of air under pressure; The valve 4 controls the flow of air to the motor 2. The shaft 5 of the motor 2 is connected through gearing, indicated at G,, ,to the shaft 'fi'whichhas bearings in the housing I and which has an'outwardly projecting portion 6 onwhich is mounted the main beltdrlving pulley 1.. A rubber, surface 6 may be provided on the pulley 'I to give a better driving engagement between the pulley 1 and the abrasive or polishing belt 9. This belt 9 is supported so that it forms a triangle and the rotation of the air motor 2 is such that the belt travel, as seen in Figurel, will be in counter clockwise direction, as indicated by the arrows. The ccrners of the triangularly arranged belt 9, which are remote from the driving pulley 1, are supported by idler pulleyslfi and II. The pulley I ,is mounted for rotation on a shaft l2 which in turn is supported by the arms [3 of a yoke member l4 pivotally mounted on the pin or shaft I5. A nut I6 is adapted to hold the shaft in.

position in a bushing I1 in the frame I, and an operating lever I8 is secured to one of the arms l3. The lower end of the arm I8 is engaged by the piston rod I9 which is carried by the piston 20. Air is supplied to the cylinder -2l'-,- which houses the piston and which is mounted on the frame I, through a pipe or conduit 22 which leads to the valve 23.- A source ofsupply of air under suitable pressure is connected to thevalve 23 through the flexible tube 24.

The pulley II is mounted on a shaft 25 carried by a yoke 26;whichis generally similar to the yoke l4, and which is pivotally supported on a shaft 21. A bushing 28 is a part of the frame Iv and the nut 29 holds the "shaft 21 in position in the bushing 28. Arm 30; isattached to the bracket 26 and is connected at its opposite end to the adjusting screw 3l bynieans of a floating link 32. The screw 3| extends through a web or flange 33 on the frame 'I'andthe adjusting nuts 34, disposed on opposite sides of the web 33, are adapted to lock the screw. 3| in various positions and, together with the'link 32 and the arm 30,.

provide a means forswinging the yoke-28 about theshaft21. Y

In the operation of the machine the nuts 34 are adjusted to locate thepulley ll properly in the desired relation to the rest of the apparatus Preferably, the pulley l I'is'locatedslightly below the surface of the cushion belt=35.' When the valve 23 is open and air under pressure is applied to the right hand end of the-cylinder 2| (Fig; 1) the piston 20 causes a force to be exerted through the piston rod [9 against the arm" 18. This swings the yoke l4 outwardlyapplying the desired tension on the belt 9. "By varying the air pressure applied to the cylinder 2| the belt tension may be varied and, when itis desired' to change belts, it is only necessary to shut off the'air supply to the cylinder 2| 'andconnect it to the atmosphere. This will immediately release the tension on the pulley l0 and permit the old belt to be removed and a new one to beinstalled. :The pulley ll remains fixed except for whatever adjustments may be found desirable to accommodate different working'conditions. P

The portion of the belt 9 between the pulleys I0 and II is the working reach of the belts; To support this sectionof belt properly I provide an endless resilient, relatively thick cushion belt 35. As is seenin Figured-this belt includes a body 35 of sponge or "foam rubber or the like carried by and vulcanized to afabric inner beltpulleys whichsupport the cushion I Spaced idler pulleys 36 and 31 are mounted on shafts 38 and 39 respectively and these shafts are carried by a sub-frame 40 secured to the main frame I of the machine by screws 4|. The main support for the cushion belt 35 is provided by the pulleys 36 and 31 and auxiliary support for the working portion of the belt is furnished by the small idler rolls 42 which are mounted on a detachable bracket structure 43 secured to the sub-frame 40 by screws 44 (see Figs. 1 and 5).

By means of the detachable sub-frame 40 the entire assembly of guide pulleys 36, 31 and 42 may be removed. The bracket 43 is slotted, as seen in Figure 1, to accommodate the screws 44 and the slotspermit adjusting of the bracket 43 and the rolls 42 toward or away from the common center line of the pulleys 36 and 31. From the above it will be seen that the cushion belt 35 is supported independently of the abrasive belt 9 with its outer surface supporting and engaging the inner surface of the belt 9. As the pulleys I0 and H are located slightly belowthe surface of the belt 35 it is possible to holdthe outer surface of the belt 9 against the work and have it cushioned by the resilient belt 35. As the belt 9 rotates over its triangularly arranged pulley supports its frictional engagement with the surface of the belt 35 will cause the latter to rotate around its supporting pulleys 36 and 31 and the small idler rolls 42 will provide additional central support for the belts 35 and 9 when and as desired. As there is substantially no slip between the belts 35 and 9 practically no frictional heat is engendered. The increase in the life of both belts results in a uniform cushioning action at all times. The foam rubber belt 35 may be removed and replaced as needed without disturbing the driving belt supporting means.

It'has been found from experience in actual production use of my machines that the rotating, relatively thick resilient foam rubber backing belt makes possible a finish on the priming coat of an automobile body which is unattainable by manual sanding.

As the surface finishing for which this machine is particularly advantageous is normally a wet sanding operation I have provided a water supply which is directed against the outer surface of the belt 9 through a pipe 45 disposed-adjacent the pulley Ill and. having suitable spray holes therein. A connecting pipe 46 leads from the spray pipe 45 to the water regulating valve 41 which in turn is connected to a suitable source of water by the flexible hose 48. It may benoted at this point that the valves 4, 23 and 41 are all mounted together on the end of the air motor 2. V This is a convenient location for these valves and facilitates thecontrol thereof by the operator. Itwill, of course, be understood that other valve locations might in some instances be desirable. 4

The handles 49 and 50 are attached to the frame I and the entire device may be supported'from overhead'by the members 5| which are pivotally' connected to the brackets 52 on the Preferably, a counter-weight is em-,

er 65. 7 I

Thepulley 56'is similarly mounted on a yoke engaging the surface, a cutjis taken whichhas a width extending substantially'from 'the point 53 'to "thew'point 54'and; due to the resiliency of the belt and the fact that it moves'with the -abrasive belt 9, this cut 'is substantially uniform 'over its entire width; This contrasts with the usual hand operation in which, when the operator moves the wet sandpaper over the surface, a materially di'lferent pressure is applied at differ'entpoints of contact of the sand paper with the surface thus giving a different cutting action at each point of different pressure. This results in uneven finishing. My abrasive belt 9, however, is uniformly supported by the resilient belt 35 and thus the cut is completely uniform except for a slight taperingoif at about the points 53 and 54 which, of course, 'is a desirablefeature as it .permits the operator to overlap his strokes and obtainan extremely uniform surface over the entire work.

Although I have particularly described the belt 35 as being made of 'a'foam or sponge rubber, it will be understood by those skilled in the art that other suitably soft or resilient materials might-be used. The thickness of the belt 35 is also a definite factor in the type of surface finishing which is obtained and I find that, when using a given material, the thicker the resilient belt the softer the cushioning effect. By arranging the sanding belt 9 in the triangular form shown I obtain sufficient space within the confines of the belt to support relatively large pulleys 36 and 31 for carrying the resilient belt 35.

The large sizes of th pulleys 36 and '31 is an important feature in making possible the use of a resilient backing belt as it prevents a sharp bending of this belt which is very detrimental to its life and efficiency regardless of the material used to make up the belt.

In Figures 7 to 12 I have illustrated a modified form of my improved sending machine. In this device a relatively long reach of sanding surface is provided and the resilient backing belt may be omitted so that convex surfaces, such as indicated in dot and dash linesat 53, in Figure 7, may be finished. The surface finishing belt 54 is supported on thre triangularly arranged pulleys 55, 56 and 51. Pulley is the driving pulley and corresponds to pulley 1 of Figure 1. Although the driving motor is not shown it will be understood that the pulley 55 maybe connected to an air motor in the same manner as illustrated in Figures 1 to 3.

The adjustable supporting pulley 51 is carried by a yoke 58 which is pivotally mounted on the main frame 59 of the machine. An arm 66 is secured to the yoke and is connected through a .link 6| to an adjusting rod 62 (see Fig. 8). In the frame 59 there is a bushing 63 through which the rod 62 extends and the lower end of rod 62 has threaded engagement with an adjusting nut 64. The clamping washer 65 may be caused to engage the top flange of the nut 64 when the screws66 are tightened. By turning the nut 64 the rod 62 is moved up or down and this movement is transmitted through the link 6| and the arm 60 to adjust the position of the pulley 51 and an effective lock is provided by wash- 61 which is pivoted to the frame 59 and an arm 68 is secured to the yoke 61 and engages the end of the piston rod 69. By applying air under pressure through the pipe 76 to the cylinder H the piston 12, which carries the piston rod 69,

causes a Sforce to'beexerted 'onthe arm 66 tend- .ing to swing thepulley56 "outwardly to tighten the belt 54; A pin or plunger 13,?ha'vingi a sliding'fitrinthe frame his held bythe compression spring 14in a position determined by the adjustment of the nut 15. "This'spring plunger opposes the actionof the piston rod 69,-

Asv is clearly seenin Figure. 10,.small transverse rolls '16 are mounted on brackets carried by theshaftl'! which also carries the roll 56. The surfaces of these small rolls 16 are slightly above the surface of the belt 54 onjthe pulley 56. Similar transverse, protectingjrolls 16 are mounted on the opposite end of the machine adjacent the pulley 51. Gouging of the surface being finished or excessive abrasive action due to direct pressure of the belt 54 against the rolls 56 and 5'! is prevented by the small rolls 16. These rolls prevent direct contact of the: belt 54 with the work at the supporting pulleys 56 and '51. The axes 'of the small rolls extend at right an,- gles to the axes of the pulleys 56 and 51 because, in operation, the machine is usually moved over to the work in a direction parallel to-the shafts which support the rolls 56 and 51. 4

Inthe apparatus shown in Figure 7 water is sprayed against the belt 54 through suitable holes in the supply pipe" which is connected to a source of supply of Water (not shown). Preferablythe air connections to the motor which drives the pulley 55 and to the cylinder H through the pipe 10, and the water connection to the spray pipe 16 are connected to valves arranged in the manner illustrated in Figure 3. The frame 59 is provided with handles 16 and 86 arranged similarly to handles 46 and 56 of Figures1and3. 1 I In Figure 11 the machineof Figur 7 ,isillustrated equipped with an auxiliary belt support-v ing roll 8|- "I'hisroll is mounted on aremov able bracket 62 secured to the .frame ,59.o'f the machine. The "resilient. foam or. sponge rubber facing 83 of this roller BI :is' secured to a] central-hub 84 by means of plates, 85 and .66-. (see Fig. 12). With the roll 8] inplace'thefmachine is adapted to sand. either flat, concave; or convex surfaces and to perform various operations which are not as readilycarried out, when} the entire reach of the belt 54. betweenth'e pulleys 56 and 5'! is unsupported. A sprayguardlfllhof flexible material, is attached to the, metal belt guard 88 and, as the belt 54 revolves incountere clockwise direction as seen in Figures '7 and 11, this prevents the material carriedalong by the belt frorn'being. splattered. on to' adjacent areas. A removable metal belt guard .89ls alsopreferably provided on the machine'offFigures 1v to 6 in order to protect the operator and prevent undesirable scattering of water, etc.

By means of the two embodiments of my inventionwhich have been illustrated and de scribed 'it is possible to finish a great variety of surfaces. No support for the sanding belt is needed other than the two small idler pulleys'and themain driving pulley. If desired th idler pulleys, aswell as the driving pulley, may be covered with rubber or other similar material tending to give a better traction of the belt on the pulleys. The bracket 43 which carries the small ans conditions which are encountered in operation. My machine'is extremely compact, rugged,

easily handled and controlled and can be operated under the necessarily wet conditions which accompany wet sanding without danger of damage to the machine or injury to the operator.

Although I have described the illustrated embodiments of my invention in considerable detail, it will be understood that numerous modifications and variations may be made in the form of apparatus employed to carry out my invention, and I do not, therefore, wish to be limited to-the particular forms herein shown and described but claim as my invention all embodiments thereof coming within the scope of the appended claims.

I claim:

l 1. In apparatus of the type described, the combination of a frame, a main driving pulley, a pair of auxiliary belt'supporting-pulleys arranged in triangular relation with said main driving pulley, fluid pressure actuated means for moving one of said pair of pulleys relative to the other of said pair of pulleys, a surfacing belt supported by and encircling said driving pulley and auxiliary supporting pulleys, and an endless, resilient sponge rubber backing belt secured to and backed by a substantially non-stretchable inner belt and supported independently of said triangularly arranged pulleys for rotation within the space defined by said surfacing belt, said backing belt engaging the inner surface of the surfacing belt between said pair of auxiliary supporting pulleys and adapted to be driven by said surfacing belt.

2. In a surface finishing device of the type described, a frame, a motormounted on said frame, a drive pulley, a supporting shaft for said pulley rigidly. carried by said frame, operating connections between said motor and drive pulley, a pair of spaced auxiliary belt supporting idler pulleys, a supporting member for one ofsaid auxiliary pulleys, means for adjusting the position of said supporting member, a second supporting member for the other of said auxiliary pulleys freely pivoted on said frame, fluid presengaging each of said pulleys and having its working portion disposed between said auxiliary pulleys, and resilient independent 'means for backing up said finishing belt between said auxiliary pulleys.

3. In a surface finishing device of the type described, a frame, an air motor mounted on said frame, a drive pulley carried by said frame, operating connections between said motor and drive pulley, a pair of spaced auxiliary belt supporting pulleys, a supporting member for one of said auxiliary pulleys, means for adjusting the position of said supporting member,-a second supporting member for the other of' said auxiliary pulleys, fluid pressure actuated meansxfor moving said second supporting member relative to said frame whereby said other auxiliary pulley may be moved away from said one of said auxiliary pulleys. said drive pulley and auxiliary pulleys being arranged in triangular relation, a surfacefinishing beltencompassing said pulleys and having its inner surface engaging each of said pulleys, a resilient backing belt, and pulley means, independent of said triangularly disposed pulleys, for supporting said backing belt, said pulley means holding said backing belt in engagement with the inner face of said surface finishing belt whereby movement of said surface finishing belt will rotate said backing belt.

4. In apparatus of the type described, a surface finishing belt, pulley means for supporting said belt comprising three triangularly arranged pulleys one of which is adjustable relative to the other two, a resilient backing belt having a relatively thick sponge rubber backing body and a substantially non-stretchable wear resisting and load carrying inner portion bonded tosaid rubber body, and independent pulley means for supporting said backing belt with said sponge rubber body in engagement with said surface finishing belt.

5. In a surface finishing device, a surface finishing belt, pulleymeans engaging the inner surface of said belt for supporting said belt, and a guard roll supported adjacent said pulley means, said r011 being disposed with its axis of rotation substantially at right angles to the axis of rotation of said pulley means and its peripheral surface extending beyond the outer surface of said belt at said pulley.

6. In a surface finishing device of the type described, a frame, a drive pulley carried by said frame, means for rotating said drive pulley, a pair of spaced auxiliary belt supporting pulleys, a supporting member for one of said auxiliary pulleys, a second supporting member for the other of said auxiliary pulleys, fluid pressure actuated means for moving said second supporting member relative to said frame whereby said other auxiliary pulley may be moved away from said one of said auxiliary pulleys, said drive pulley and auxiliary pulleys being arranged in triangular relation, a surface finishing belt encompassing said pulleys, a resilient backing belt, and means, independent of said triangularly disposed pulleys, for supporting said backing belt.

7. In a surface finishing device of the type described, a frame, a motor mounted on said frame, a drive pulley, a supporting shaft for said pulley rigidly carried by said frame, operating connections between said motor and drive pulley, a pair of spaced auxiliary belt supporting idler pulleys, a supporting member-for one of said auxiliary pulleys, means for adjusting the position of said supporting member, a second supporting member for the other of said auxiliary pulleys freely pivoted on said frame, fiuid pressure actuated means for moving said second supporting member relative to said frame whereby said other auxiliary pulley may be moved away from said one of said auxiliary pulleys, said drive pulley and auxiliary pulleys being arranged in triangular relation, and a surface finishing belt encompassing said pulley with its inner surface engaging each of said pulleys and having its working portion disposed between said auxiliary pulleys.

' BERT'F. FOWLER. 

